Patent GB-1240126-A (GB)
Title: Improvements in or relating to switching elements for a hydraulic or pneumatic control system
Inventor: PASCHKE HANNS-DIETER
IPC: F15C3/00
Filed: 1968-09-10
Abstract: 1,240,126. Valves. H. D. PASCHKE. 10 Sept., 1968 [13 Sept., 1967; 26 Jan., 1968; 16 Feb., 1968], No. 42903/68. Heading F2V. [Also in Division G4] An N-type hydrosistor (Fig. 1) comprises a cylindrical housing 2 with end surfaces 3, 4 to which control line 5 and output line 6 are connected; the aperture of the latter being surrounded by annular groove 7 connected to input line 8 and the interior containing a loose disc 9 sealing to either end surface. The control and input lines are connected to system pressure and since the pressure surface of the underside of the disc is less than that of the upper side by the cross-section area of the output line, the disc normally closes the output line from the input line until the control line is depressurized, when it rises (Fig. 2, not shown) to close the control line and open the input line to the output line; the disc being returned on repressurization. The groove may be formed in the underside of the disc, or replaced by annularly disposed bores, and may be connected to output line with input line opening centrally into 2. The device may be symbolized (Fig. 3) wherein ST denotes control, P input and X output. A P-type hydrosistor (Fig. 4) comprises cylindrical housing 2<SP>1</SP> partitioned at 14 into chambers 15, 16; the latter containing discs 17, 18 linked by distance piece 20 located in clearance aperture 19. Control line 5<SP>1</SP> enters chamber 15 and output line 6<SP>1</SP> leaves clearance aperture 19<SP>1</SP>, while input line 8<SP>1</SP> enters chamber 16. Connection of line 5<SP>1</SP> to tank or relief allows input pressure to lift disc 18 to seal aperture 19, while lifting disc 17. Excess pressure of output line 6<SP>1</SP> over control line 5<SP>1</SP> seals the latter, and input line is closed from the output line. System pressure on the control line depresses disc 17 to close aperture 19, since pressure area of disc 17 exceeds that of 18, while disc 18 is depressed by the distance piece to open the input line to the output line. The valve disc surfaces may be rounded or tapered, and the device may be symbolized (Fig. 6) wherein ST<SP>1</SP> denotes control, P<SP>1</SP> input and X<SP>1</SP> output. A linear action motor (Fig. 7, not shown) may be controlled and locked in lateral motion by four paired n-type hydrosistors with the control lines of the respective pairs interconnected, the inputs and outputs of corresponding units of each pair being connected between pressure and each side of a piston and between tank and each side of the piston; respectively, while the controls of respective pairs are connected to switching lines R, S respectively; connection of the latter to pressure and tank or vice versa driving the piston in either direction while connection of both lines to pressure locks the system. A positive AND circuit (Fig. 8) comprises pairs I, II of N and P hydrosistors A and B wherein the P-type are series and the N-type are shunt connected; input P 1  of B 1  being derived from pressure source and output X<SP>1</SP> of B II  connected to consumer V; the output X<SP>1</SP> of B I  being connected to input P 1  of B II ; while inputs P of A I , A II  are connected to consumer and outputs X to tank O. Zero pressure in control lines R, S opens A I A II  while closing B I B II  so that V is connected to O, and pressure on R or S closes A I  or A II  and opens B I  or B II , but V remains connected to O. Pressure on both R and S closes A I A II  and opens B I B II  to apply pressure to V. A positive OR circuit (Fig. 10, not shown) is similar but with the input of B II  connected to pressure, the output of A II  connected to the input of A I  and the output of B I  connected to V. V is connected to O for zero control while V is connected to pressure for control on R, S or both lines. A negator (Fig. 12, not shown) comprises a pair of N and P hydrosistors wherein the inputs of the first is connected to pressure, the input of the second and output of the first being connected to V, and the output of the second being connected to tank, while the controls are connected to a common line, on which pressure connects V to O and removal of pressure connects V to supply. A positive relay (Fig. 14, not shown) operates similarly and reversedly. Negative AND and OR circuits (Figs. 15, 16, not shown) are formed by rearrangement of the N and P hydrosistor pairs of Fig. 8. A combined N=P hydrosistor (Fig. 17), comprises housing 1<SP>11</SP> chambered at 15<SP>1</SP>, 16<SP>1</SP> divided by partition 14<SP>1</SP> centrally apertured at 19<SP>1</SP> to admit a distance piece 20<SP>1</SP> supporting spaced valve discs 17<SP>1</SP>, 18<SP>1</SP>. Control line 5<SP>1</SP> opens to the end of chamber 15<SP>1</SP> and input line 8<SP>1</SP> into the side of chamber 16<SP>1</SP> near the partition, while output line 6<SP>11</SP> opens centrally from aperture 19<SP>1</SP>. A relief line 30 connectible to tank or atmosphere opens to the surface of partition 14<SP>1</SP> limiting chamber 15<SP>1</SP>; which surface has an arcuate recess 6a partly surrounding the opening and communicating with the aperture 19<SP>1</SP> and output line 6<SP>11</SP>. Absence of pressure on control line 5<SP>11</SP> allows disc 18<SP>1</SP> to close input line 8<SP>11</SP> from output line 6<SP>11</SP> while opening latter to relief line 30 and closing control line 5<SP>11</SP>. Pressure on latter closes disc 17<SP>1</SP> on seat 211 to close output line 6<SP>11</SP> from relief line 30, while lifting disc 18<SP>1</SP> to connect input line 8<SP>11</SP> to output line 6<SP>11</SP>, so that presence or absence of control pressure applies system or zero pressure to output line 6<SP>11</SP>. The device may be symbolized (Fig. 19) wherein ST<SP>11</SP> represents control, P<SP>11</SP> input, X<SP>11</SP> output and Y the relief line. Two N-P hydrosistors of this kind may form an AND circuit (Fig. 20, not shown) or an OR circuit (Fig. 21, not shown). A modification of the N hydrosistor of Fig. 1 to P-N operation (Fig. 22, not shown) comprises a further disc valve operated over a distancepiece by the main disc valve to connect the output line to an output aperture or to a relief aperture. Control pressure opens connection between input and output while closing connection between relief line and output aperture. Zero control pressure closes connection between output line and the further disc valve, operating the latter to close the relief line, whereby pressure fluid is delivered through the output aperture to the consumer, which receives alternately system pressure or relief pressure. The device may be connected in the logic of Figs. 20, 21 (not shown).